Carboxylation of fluorene

ABSTRACT

Method of carboxylating a compound of the group of R-C*CH, RCH2CN, indene, cyclopentadiene or fluorene, where R is hydrocarbyl, comprising contacting said compound with carbon dioxide under substantially anhydrous conditions in the presence of a base of the formula: WHERE X is sodium or potassium, R1 is hydrogen or alkyl and subsequently acidifying the resultant reaction product to form the carboxylated product.

United States Patent Patmore et al.

[451 Sept. 19, 1972 [54] CARBOXYLATION OF FLUORENE [72] Inventors: Edwin L. Patmore; William R.

Siegart; Harry Chaletz, all of Texaco Inc. PO. Box 509, Beacon, N.Y. 12508 [22] Filed: Feb. 3, 1971 [21] Appl.No.: 119,430

Related US. Application Data [62] Division of Ser. No. 784,901, Dec. 18, 1968,

Pat. No. 3,595,907.

[52] US. Cl. ..260/515 R Primary Examiner-James A. Patten Enemy-K. E. Kavanagh et al.

[57] ABSTRACT Method of carboxylating a compound of the group of R-C :CH, RCl-l CN, indene, cyclopentadiene or fluorene, where R is hydrocarbyl, comprising contacting said compound with carbon dioxide under substantially anhydrous conditions in the presence of a base of the formula:

where X is sodium or potassium, R is hydrogen or alkyl and subsequently acidifying the resultant reaction product to form the carboxylated product.

4 Claims, No Drawings CARBOXYLATION OF FLUORENE This is a division of Ser. No. 784,901 filed Dec. 18, 1968, now matured to U.S. Pat. No. 3,595,907.

BACKGROUND OF THE INVENTION SUMMARY OF INVENTION We have discovered a method of carboxylating organic compounds of the group of RC 5 CH, RCl-l CN, indene, cyclopentadiene or fluorene, where R is alkyl, aryl, alkaryl and aralkyl of from one to carbons consisting essentially of contacting said organic compounds with carbon dioxide under substantially anhydrous conditions in the presence of a base of the formula:

where X is sodium or potassium and R is hydrogen or alkyl of from one to 12 carbons, and subsequently acidifying the resultant reaction mixture to recover the carboxylic acid. The'discovery that the sodium and potassium phenoxide salts facilitate the production of carboxylated products in high yields has rendered a base catalyzed carboxylation process for the starting materials contemplated herein commercially feasible since the phenoxide is many times less expensive than the previous bases employed.

DETAILED DESCRIPTION OF THE INVENTION Specifically, the invention relates to contacting essentially in the absence of water an active hydrogen containing organic compound of the group RC CI-I, RCH CN, indene, cyclopentadiene or fluorene with a phenoxide of the formula:

where R, R and X are as heretofore defined with carbon dioxide preferably in excess and subsequently acidifying the resultant mixture to respectively form carboxyl compounds of the group of R--C C- COOI-I,

COOH

indene-S-carboxylic acid, tricyclo[ 5.2.1.01 decal-3,8- diene-4,9-dicarboxylic acid and tricyclo[5. 2.l.0

deca-3,8-diene-5,S-dicarboxylic acid, or fluorene-9- carboxylic acid. The carbonation advantageously takes place at a temperature between about 0 and l50C., preferably between about and 50C., under a carbon dioxide pressure of between about 1 to 200 atmospheres, preferably between I and 25 atmospheres, utilizing a mole ratio of phenoxide to organic compound of between about 1:1 and 20:], preferably between 1:] and 5:1, and an excess of carbon dioxide. Advantageously, the reaction mixture is acidified desirably at a temperature betweenabout 5 and 35C. to a pH of less than 6, preferably between about I and 3, to insure complete conversion of the intermediate alkali metal salt to the desired acid product. Although the reaction may be conducted in the absence of solvent, an inert liquid solvent is preferably used in amounts of between about 50 and 90 wt. of thereactent of less than about 0.5 wt. based on the reaction mixture during carbonation is intended.

Examples of the organic reactant compounds contemplated herein are phenylacetylene, benzyl cyanide, acetonitrile, hexanenitrile, acetylene, l-butyne and 1 hexyne.

Examples of the base constituents are potassium and sodium salts of phenol, methylphenol, methylphenol, toctylphenol, nonylphenol and dodecylphenol.

Specific examples of the acidifying acids contemplated herein are the mineral acids such as hydrochloric acid, nitric acid, sulfuric acid and hydrobromic acid in aqueous concentrations ranging from 4 to 96 weight percent.

- Specific members of the inert liquid solvents contemplated herein are N,N-dimethylformamide, hexarnethylphosphoramide, dimethyl sulfoxide, diphenyl sulfoxide, dimethyl sulfone and N,N-dimethylacetamide. The solvent during the carbon dioxide contact advantageously constitutes between about 50 and wt. of the reaction mixture.

During the carbon dioxide contact the gas is normally passed through the reaction mixture in a liquid state. However, alternatively, the organic reaction mixture may be sprayed into an atmosphere of carbon dioxide or the carbon dioxide may be passed over a solid or liquid surface which is desirably continually changed by agitation in order to form a fresh surface for contact.

The carboxylic acid products are recovered from the reaction mixture by standard means such as selective extraction, distillation, decantation and combinations thereof. Specific examples of the carboxylic acid products contemplated herein are indene-B-carboxylic acid, tricyclo[5.2. l .0 ]deca-3,8-diene-4,9-dicarboxylic acid and tricyclo[5.2.l.0"]deca-3,8-diene-5,5- dicarboxylic acid, phenylpropiolic acid a-phenylcyanoacetic acid, cyanoacetic acid, a-cyanohexanoic acid, 9-fluorene carboxylic acid, 2-butynoic acid, 2- propynoic acid and 2-hexynoic acid.

The following examples further illustrate the invention but are not to be considered as limitations thereof.

EXAMPLE I This example illustrates the preparation of indene-3- carboxylic acid from indene.

To a 3-necked round bottomed flask equipped with magnetic stirrer, thermometer, water cooled condenser and a gas sparger, the condenser connected to a mercury bubbler to protect the system from atmosphere, 3.5 grams of indene, 15 .8 grams of potassium phenoxide, and 75 mls. of dimethylfonnamide were charged. The resultant mixture had a water content of less than 0.5 wt. '91:. An excess of dried carbon dioxide was bubbled through the reaction mixture under atmospheric pressure over a period of 5 hours. At the inception of carbon dioxide introduction, the reaction mixture was at room temperature (about 26C.). The temperature increased from room temperature to 45C. within 5 minutes after introduction. Within 8 minutes after introduction the temperature dropped to 28C. and thereafter remained during the entire reaction period between 26 and 28C.

At the end of the 5 hour period the reaction mixture was poured into a mixture of 80 mls. of concentrated hydrochloric acid and 100 grams of ice overlaid with 100 mls. of ether. The temperature of acidification was about C. The layers were separated and the aqueous layer extracted with ether (5x100 mls.). The ether extracts were combined with the first organic layer. The combined ether organic layers were extracted, 10 wt. sodium bicarbonate (5x100 mls) and the sodium bicarbonate extracts were then acidified (to a pH of 1 to 3) with 6M l-lCl while keeping the entire mixture cooled in an ice-water bath. The combined acidified sodium bicarbonate extracts were then extracted into ether (5X100mls), dried and the ether removed on a rotary evaporator to give the crude carboxylated product. Recrystallization of the crude product from benzene gave a yield of 1.79 grams of indene-3-carboxylic acid corresponding to a yield of 37.4 mole The structure of the indene-3-carboxylic acid product was confirmed by its melting point of 157C. (lit. 158l60C.) and its infrared and nuclear magnetic resonance spectra.

EXAMPLE II This is a description of the preparation of phenylpropiolic acid from phenylacetylene.

The carbon dioxide contact, acidification and recovery was the same as that used in Example I with the following exceptions:

To the 3-necked flask there was charged 3.1 grams of phenylacetylene, 15.8 grams potassium phenoxide and 75 mls. of dimethylformamide. Upon charging of the first three reactants, the temperature rose from 27 to 31C. and the solution became dark brown. The water content therein was less than 0.5 wt. Then dried carbon dioxide in excess was bubbled into the mixture and the temperature rose to 43C. in 4 minutes and gradually returned to 32C. at the end of the first hour. The temperature held at 3lC.'for the next 2 hours. Total carbonation time was 3 hours at a temperature in the range of 3143C.

The product after acidification and work-up was 1.6 grams of phenylpropiolic acid representing a yield of 37 molepercent having a melting point of l37-138C. (lit. rn.p. l37l39C.), a carbon content of 73.9 wt. (74% calc.), a hydrogen content of 4.2 wt. (4.1% calc.) and an infrared spectrum identical to phenylpropiolic acid.

EXAMPLE Ill This example illustrates the preparation of cit-phenylcyanoacetic acid from benzyl cyanide.

The procedure of Example I was essentially repeated with the following exceptions:

To the reaction flask there was charged 3.5 grams of benzyl cyanide, 15.8 grams potassium phenoxide, and mls. of dimethylformamide. The resultant mixture had a water content less than 0.5 wt. Within 3 minutes of charging the reactants to the flask the temperature rose from 31 to 45C. and dropped to 32C. over the next 19 minutes. Thereafter, the temperature during carbon dioxide bubbling remained between 28 and 32C. for the reaction period. The total carbonation time was 4 hours. The temperature ranged in this 4 hour period between 48 and 45C.

After acidification and work-up a solid was recovered in an amount of 2.7 grams and was determined to be a-phenylcyanoacetic acid in a yield of 56 mole percent. The a-phenylcyanoacetic acid had a melting point of 92.5-93.5C. (lit. m.p. 92C.) and infrared and nuclear magnetic resonance spectra which confirmed it to be a-phenylcyanoacetic acid. Elemental analysis found 67 wt. C (calc. 67), 4.3 wt. l-l(cal. 4.3) and 8.8 wt. N (calc. 8.7).

EXAMPLE IV This example illustrates the conversion of cyclopen tadiene to tricyclo [5.2.1.O ]deca-3,8-diene-4,9 dicarboxylic acid better known as Thieles acid and a minor amount of tricyclo [5.2.l.0 "]deca-3,8-diene- 5,5-dicarboxylic acid.

The procedure employed was that of Example I with the following exceptions:

There were introduced into the reaction flask 31.6 grams potassium phenoxide, 4.0 grams cyclopentadiene and mls. of dimethylformamide. The resultant mixture had a water content of less than 0.5 wt. During carbon dioxide contact the temperature ranged from 33 to 47C. over a period of 3 hours. The amount of carbon dioxide employed was in excess of that required for the complete conversion of the cyclopentadiene reactant to the carboxylic acid derivative.

One product recovered after work-up was determined to be Thieles acid in an amount of 3.1 grams representing a 47 mole percent yield and having a melting point of l9920lC. (lit. m.p. 197-l99C.). lts nuclear magnetic resonance and infrared spectra confirmed it to be Thieles acid. A minor amount of tricyclo [5.2. l .0 ']deca-3,8-diene-5 ,5-dicarboxylic acid was also found.

EXAMPLE V This example further illustrates the method of the invention and is directed to a series of runs of the type found in Examples I-lV except sodium phenoxide is substituted for potassium phenoxide.

The test data and results are reported below in Table No. 3. -mls. g. C. Hrs. 11 Yield A 27.8 I ID. 32-60 |C.49

7.0 g B 13.9 75 BC, 33-48 5 PC.60 3.5 g C 13.9 75 PA. 30-43 4 PP.58

6.2 g D 27.8 125 CP. 33-53 4 T,43

4.0 g DMF =Dimethylform amide ID lndene BC Benzyl Cyanide PA Phenylacetylene C? Cyclopentadiene IC lndene-3-carboxylic acid PC a-Phenylcyanoacetic acid PP Phenylpropiolic acid T Thiele's Acid EXAMPLE Vl This example illustrates the criticality of the particular combination of base and organic reactant in the production of carboxylic acids.

The procedure employed is essentially that described in Example I. The test data and results are reported below in Table II:

Ill-400 Pol styrene quaternary amine p-NT p-n trotoluene CH Cyclohexunone FL Fluorene PA Phcnylucetylene ID lndene As can be seen from the above table, substitution of organo and base reactants of a closely related nature for those contemplated herein fail to produce a carboxylic acid derivative.

We claim:

1. A method of producing fluorene-3-carboxylic acid comprising contacting fluorene with carbon dioxide under substantially anhydrous conditions in the presence of the base of the formula:

where X is sodium or potassium and R is hydrogen or alkyl of one to 12 carbons, at a temperature between about 0 and 150C. under a carbon dioxide pressure betwee n about 1 and 200 atmospheres utilizing a mole ratio 0 base to organic compound of between about 1:1 and 20:1, subsequently acidifying the resultant reaction mixture to a pH of less than about 6 and recovering the carboxylic acid compound from the acidified mixture.

2. A method in accordance with claim 1 wherein said acidifying is conducted to a pH of between about 1 and 3 3. A method in accordance with claim 2 wherein said acidifying is conducted with hydrochloric acid.

4. A method in accordance with claim 3 wherein said CO, contacting is conducted in the presence of between about 50 and 90 wt. dimethylformamide. 

2. A method in accordance with claim 1 wherein said acidifying is conducted to a pH of between about 1 and
 3. 3. A method in accordance with claim 2 wherein said acidifying is conducted with hydrochloric acid.
 4. A method in accordance with claim 3 wherein said CO2 contacting is conducted in the presence of between about 50 and 90 wt. % dimethylformamide. 